chore: organize solution into module folders (Core/Server/Drivers/Client/Tooling)

Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.

- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
  the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
  mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
  integration, install).

Build green (0 errors); unit tests pass. Docs left for a separate pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Services/ReservationService.cs

@@ -0,0 +1,38 @@
+using Microsoft.Data.SqlClient;
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Fleet-wide external-ID reservation inspector + FleetAdmin-only release flow per
+///     <c>admin-ui.md §"Release an external-ID reservation"</c>. Release is audit-logged
+///     (<see cref="ConfigAuditLog"/>) via <c>sp_ReleaseExternalIdReservation</c>.
+/// </summary>
+public sealed class ReservationService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<ExternalIdReservation>> ListActiveAsync(CancellationToken ct) =>
+        db.ExternalIdReservations.AsNoTracking()
+            .Where(r => r.ReleasedAt == null)
+            .OrderBy(r => r.Kind).ThenBy(r => r.Value)
+            .ToListAsync(ct);
+
+    public Task<List<ExternalIdReservation>> ListReleasedAsync(CancellationToken ct) =>
+        db.ExternalIdReservations.AsNoTracking()
+            .Where(r => r.ReleasedAt != null)
+            .OrderByDescending(r => r.ReleasedAt)
+            .Take(100)
+            .ToListAsync(ct);
+
+    public async Task ReleaseAsync(string kind, string value, string reason, CancellationToken ct)
+    {
+        if (string.IsNullOrWhiteSpace(reason))
+            throw new ArgumentException("ReleaseReason is required (audit invariant)", nameof(reason));
+
+        await db.Database.ExecuteSqlRawAsync(
+            "EXEC dbo.sp_ReleaseExternalIdReservation @Kind = {0}, @Value = {1}, @ReleaseReason = {2}",
+            [kind, value, reason],
+            ct);
+    }
+}